Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/48—Preparations in capsules, e.g. of gelatin, of chocolate
  • A61K9/50—Microcapsules having a gas, liquid or semi-solid filling; Solid microparticles or pellets surrounded by a distinct coating layer, e.g. coated microspheres, coated drug crystals
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/48—Preparations in capsules, e.g. of gelatin, of chocolate
  • A61K9/50—Microcapsules having a gas, liquid or semi-solid filling; Solid microparticles or pellets surrounded by a distinct coating layer, e.g. coated microspheres, coated drug crystals
  • A61K9/5005—Wall or coating material
  • A61K9/5021—Organic macromolecular compounds
  • A61K9/5026—Organic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/335—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin
  • A61K31/34—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin having five-membered rings with one oxygen as the only ring hetero atom, e.g. isosorbide
  • A61K31/341—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin having five-membered rings with one oxygen as the only ring hetero atom, e.g. isosorbide not condensed with another ring, e.g. ranitidine, furosemide, bufetolol, muscarine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/48—Preparations in capsules, e.g. of gelatin, of chocolate
  • A61K9/50—Microcapsules having a gas, liquid or semi-solid filling; Solid microparticles or pellets surrounded by a distinct coating layer, e.g. coated microspheres, coated drug crystals
  • A61K9/5005—Wall or coating material
  • A61K9/5021—Organic macromolecular compounds
  • A61K9/5036—Polysaccharides, e.g. gums, alginate; Cyclodextrin
  • A61K9/5042—Cellulose; Cellulose derivatives, e.g. phthalate or acetate succinate esters of hydroxypropyl methylcellulose
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P1/00—Drugs for disorders of the alimentary tract or the digestive system
  • A61P1/04—Drugs for disorders of the alimentary tract or the digestive system for ulcers, gastritis or reflux esophagitis, e.g. antacids, inhibitors of acid secretion, mucosal protectants
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P17/00—Drugs for dermatological disorders
  • A61P17/04—Antipruritics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P29/00—Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P37/00—Drugs for immunological or allergic disorders
  • A61P37/08—Antiallergic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/0002—Galenical forms characterised by the drug release technique; Application systems commanded by energy
  • A61K9/0007—Effervescent
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/20—Pills, tablets, discs, rods
  • A61K9/2072—Pills, tablets, discs, rods characterised by shape, structure or size; Tablets with holes, special break lines or identification marks; Partially coated tablets; Disintegrating flat shaped forms
  • A61K9/2077—Tablets comprising drug-containing microparticles in a substantial amount of supporting matrix; Multiparticulate tablets
  • A61K9/2081—Tablets comprising drug-containing microparticles in a substantial amount of supporting matrix; Multiparticulate tablets with microcapsules or coated microparticles according to A61K9/50

Definitions

• This invention relates generally to ph.armaceutic.al compositions in the form of microcapsules, and more particularly relates to such microcapsules in which the taste of the drug contained therein is tastemasked.
• the invention additionally relates to pharmaceutical formulations containing the microcapsules, including effervescent formulations, and to a process for masking the taste of drugs using a phase separation-coacervation technique .
• BACKGROUND ART A number of methods .are known for masking the taste of drugs; this is an increasingly important issue in the area of patient compliance with recommended pharmaceutical therapies. As explained by M.
• taste masking techniques may be broadly divided into physical, chemical, biochemical and organoleptic methods. The technique to be adopted will depend on several factors, but primarily on the extent of bitterness of the drug to be incorporated into an oral pharmaceutical formulation.
• Organoleptic methods of taste-masking involve addition of a flavoring and/or sweetening agent and as such are relatively simple. However, simple addition of a taste-masking agent such as a flavoring agent or sweetener is frequently not useful by itself, unless the drug to be tastemasked is not particularly bitter. Recent biochemical methods involve the use of lipoproteins to react with bitterness receptor sites, thereby suppressing the response to the drug's bitterness. The most common masking methods, however, are based on physical means, including agglomeration, coating, and microencapsulation.
• Microencapsulation is essentially a process by which coatings are applied to small particles of solids, droplets of liquids or dispersions, so as to form microcapsules; the technique differs from other coating procedures in that the size of the particles generally ranges from several tenths of a ⁇ m to 5000 ⁇ m in diameter.
• the present invention involves the use of a microencapsulation technique to taste mask drugs in an oral pharmaceutical formulation.
• the microencapsulation technique is a coacervation-phase separation process which involves utilization of three phases: a "core material” phase of the drug to be encapsulated; a “coating material” phase of the substance which will ultimately form the coating; and a liquid phase in which the core and coating materials are dispersed or dissolved.
• the coating is then deposited on the core material, and a desolvation process is used to remove the liquid phase and isolate the microcapsules.
• the present invention makes use of materials and process parameters which enable preparation of uniform, impervious coatings, and involves preparation of formulations having high coating levels.
• the invention provides for extremely effective taste masking while also providing for release of drug shortly after the drug passes through the mouth.
• it is very unusual and quite difficult to achieve fast drug release with high coating levels effective in taste masking.
• the invention having achieved these objectives, thus provides for an important advance in the art, enabling effective taste masking of a variety of drugs.
• U.S. Patent No. 5,075,114 to Roche describes a fluidized bed method of coating a pharmaceutical agent for taste-masking purposes.
• the patent describes the coating as a blend of cellulosic materials, i. e., hydroxypropyl cellulose and either cellulose acetate, cellulose acetate butyrate, or both.
• a number of drugs are mentioned, including ibuprofen, loperamide, famotidine, cimetidine, and ranitidine.
• U.S. Patent No. 5,082,669 to Shirai et al. describes ethyl cellulose coatings for bitter-tasting drugs. A number of drugs are mentioned as possibilities (at column 3, lines 13-31), including cimetidine.
• the coating is prepared using either a film-forming solution or dispersion, or a spraying technique (column 5, lines 36-50).
• a spraying technique column 5, lines 36-50.
• a method for making microencapsulated drugs using a "wall forming material" which may be cellulosic (column 3, line 22) in conjunction with a solvent such as methylene chloride.
• the method is stated to be useful in connection with a wide variety of drugs, including gastrointestinal therapeutic agents.
• U.S. Patent Nos. 4,389,331 and 4,542,042 to Samejima et al. describe a method for encapsulating drugs with ethyl cellulose using a phase separation technique.
• phospholipids are used to induce phase separation; in the '042 patent, another type of compound is used, i.e., a hydrocarbon such as a wax, butyl rubber, or polyethylene is used.
• microcapsules for oral administration of a drug, preferably a water-soluble drug, wherein the microcapsules have high coating levels but are nevertheless effective to achieve rapid release of drug.
• H2 antagonists such as ranitidine or a pharmaceutically acceptable acid addition salt thereof, in taste-masked form. It is still another object of the invention to provide a method for manufacturing an oral pharmaceutical formulation comprising microcapsules in which the drug contained therein is taste masked.
• FIG. 1A, FIG. IB, FIG. 1C, and FIG. ID depict the average scores for the evaluation described in Example 6 of taste masking, bitterness, aftertaste, and overall acceptance, respectively, of ranitidine microcapsule compositions.
• FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D depict the median scores for the evaluation described in Example 6 of taste masking, bitterness, aftertaste, and overall acceptance, respectively, of ranitidine microcapsule compositions.
• FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D depict the average scores for the evaluation described in Example 6 of taste masking, bitterness, aftertaste, and overall acceptance, respectively, of ranitidine tablet formulations.
• FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D depict the median scores for the evaluation described in Example 6 of taste masking, bitterness, aftertaste, and overall acceptance, respectively, of ranitidine tablet formulations.
• a polymeric material includes a mixture of two or more polymeric materials
• reference to “a solvent” includes reference to two or more solvents
• reference to “an excipient” or “a vehicle” includes mixtures of excipients or vehicles
• reference to “a drug” includes reference to two or more drugs, and the like.
• drug as used herein is meant to include any therapeutic or otherwise active agents, preferably a pharmaceutical compound or chemical that is capable of being orally administered.
• Drugs useful in conjunction with the present invention include antibiotics, antiviral agents, analgesics, anesthetics, anorexics, antiarthritics, antiasthmatic agents, anticonvulsants, antidepressants, antidiabetic agents, antidiarrheals, antihistamines, anti-inflammatory agents, antinauseants, antineoplastics, antiparkinsonism drugs, antipruritics, antipsychotics, antipyretics, antispasmodics, H 2 antagonists, cardiovascular drugs, antiarrhythmics, antihypertensives, ACE inhibitors, diuretics, vasodilators, hormones, hypnotics, immunosuppressives, muscle relaxants, parasympatholytics, parasympathomimetics, psychostimulants, sedatives, antimigrane agents anti
• the drugs used in conjunction with the present methodology are those which are bitter or otherwise unpleasant-tasting and thus in need of taste masking.
• Specific such drugs include ranitidine, cimetidine, famotidine, guaifenesin, loperamide hydrochloride, nizetidine, dimenhydrinate, caffeine, theophylline, acetaminophen and ibuprofen.
• the term "drug” is also intended to include nutritional supplements, particularly those in the vitamin B family and vitamin C.
• an “effective” amount of drug is meant a nontoxic but sufficient amount of a compound to provide the desired therapeutic or prophylactic effect.
• polymer as used herein is intended to include both oligomeric and polymeric materials, i. e., compounds which include two or more monomeric units. The term is also intended to include “copolymeric” materials, i.e., containing two or more different monomeric units.
• Carriers or “vehicles” as used herein refer to carrier materials suitable for oral drug administration, and include any such materials known in the art, e.g., diluents, binders, granulating agents, disintegrants, lubricating agents, colorants, flavoring agents, and the like.
• microencapsulation is used to refer to a process for forming coated drug particles.
• microcapsules so formed may be in the nature of a drug core having a polymeric coating thereon; alternatively, the capsules may comprise polymer matrices containing infiltrated drug.
• pharmaceutical formulation refers to formulations containing the microcapsules of the invention in combination with carriers or excipients suited to a selected drug delivery platform, e.g., an effervescent formulation, a chewable tablet, a fast-melting formulation, or the like. "Microencapsulation conducted by phase separation" and
• coating intends an encapsulation process in which drug is dispersed in a solution containing a coating material, and procedures are then followed which result in deposition of the coating on the core material.
• the microcapsules of the invention are prepared by first admixing the selected drug, a first polymeric material to serve as the coating, and a second polymeric material to promote phase separation, in a nonpolar organic solvent. Mixing is preferably conducted along with stirring or agitation using any number of conventional means.
• the solvent should be one in which the polymeric materials are soluble at higher temperatures, i. e. , temperatures generally on the order of 70°C or higher, but insoluble at ambient temperature; also, the drug should be substantially insoluble in the solvent at all temperatures used in the manufacturing process.
• a particularly preferred solvent for the present purpose is cyclohexane; however, it will be appreciated by those skilled in the art that other nonpolar organic solvents are also effective and could be used as well.
• the relative quantities of drug and first polymeric material are such that the microcapsules contain approximately 30 wt. % to 65 wt. % first polymeric material, preferably 40 wt. % to 60 wt. % first polymeric material, and most preferably 45 wt. % to 55 wt. % first polymeric material.
• effective taste masking of drug is achieved.
• the suspension so formed is heated for a time period and to a temperature sufficient to dissolve the first and second polymeric materials in the solvent.
• stirring is preferably continued at a predetermined stirring rate; a suitable stirring rate may be readily determined by one skilled in the art.
• the temperature is at or below the boiling point of the solvent; generally the components will be heated to a temperature of 70° or higher, and preferably to a temperature of at least about 75°C. However, care must be taken not to heat to a temperature which could degrade the drug (for ranitidine hydrochloride, temperatures higher than about 85 °C should be avoided). Cooling is then effected at a rate and to a temperature sufficient to effect phase separation of the first polymeric material and microencapsulation of the drug therein, forming a dispersion of microencapsulated drug. It will be appreciated by those skilled in the art that the cooling rate can be varied to optimize properties of the microcapsules, e.g. , with respect to aggregation, flowability and release profile.
• the solvent and second polymeric material are then removed by decanting, filtering or the like, followed by washing with solvent to remove any traces of the second polymeric material, and then drying, again at a temperature not so high that the drug or coating material could be adversely affected. Drying is usually although not necessarily conducted for at least about 6 hours, and longer for large-scale batches, at a temperature generally in the range of approximately ambient temperature to 60°C. Drying may or may not be conducted under reduced pressure.
• a variation on the aforementioned procedure provides a valuable alternative method which may be preferred for heat-sensitive drugs. This alternative procedure involves dissolving the first and second polymeric materials in the selected nonpolar organic solvent, without addition of drug, followed by heating to a temperature effective to dissolve the polymers. Drug is then added, the mixture is then allowed to cool, and the remainder of the procedure described above is carried out.
• the selected drug is typically a bitter or otherwise unpleasant treating drug such as ranitidine, cimetidine, or the like.
• the drug may also be in the form of a pharmaceutically acceptable salt, typically an acid addition salt such as may be formed by treating the base form of the drug with a stoichiometric excess of a selected acid.
• Such acid addition salts may be prepared, for example, with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like, or with organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, malic acid, malonic acid, succinic acid, maleic acid, hydroxymaleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, p-toluenesulfonic acid, naphthalene-2-sulfonic acid, salicylic acid and the like.
• inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like
• organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, malic acid, malonic acid, succinic acid, maleic acid, hydroxymaleic acid, fuma
• pharmaceutically acceptable salts may be prepared with bases such as potassium hydroxide, ammonium hydroxide, magnesium hydroxide, sodium hydroxide, calcium hydroxide, with naturally occurring amines such as trimethylamine, diethylamine, ethanolamine, with basic ion exchange resins, or the like. While any number of drugs can be used in conjunction with the present process and formulations, certain preferred drugs are water- soluble, i. e. drugs which are soluble or very soluble in water according to the definitions of the terms "soluble” or "very soluble” as defined in the United States Pharmacopeia, XXIII edition.
• one gram of a soluble drug can be dissolved in 30 ml of water, and preferably in 10 ml of water, at 20-25 °C, whereas one gram of a very soluble drug can be dissolve in 1 ml of water, also at 20-25 °C.
• the preferred water soluble drugs used in the present invention are those having solubility of one gram of drug in 30 ml, more preferably in 10 ml and most preferably in 1 ml of water at 20-25 °C.
• the drugs have relatively low molecular weight, below 5000, preferably below 1000 and preferably below 500.
• the present invention is particularly useful with those drugs having an unpleasant taste.
• Rl , R2 and R3 may be the same or different.
• Other bitter tasting compounds include certain salts and glycosides.
• the H 2 - antagonists discussed below are bitter-tasting compounds.
• H 2 - antagonists are water-soluble H 2 - antagonists, more preferably H 2 - antagonists selected from the group consisting of ranitidine; famotidine; cimetidine; nizatidine.
• Pharmaceutically acceptable water-soluble salts of such H 2 - antagonists and combinations of such H 2 -antagonists and/or s ts may also be employed.
• Pharmaceutical compositions prepared with the H2antagonist ranitidine, and particularly ranitidine hydrochloride, are particularly preferred herein.
• ranitidine and other aminoalkyl furan derivatives have been identified as inhibitors of the secretion of gastric acid when stimulated via histamine H 2 -receptors.
• the '658 patent also indicates that ranitidine and analogs thereof are useful in the treatment of conditions where there is a hypersecretion of gastric acid, e.g., in gastric and peptic ulceration, in the treatment of allergic conditions where histamine is a known mediator, and in the treatment of allergic and inflammatory conditions such as urticaria.
• the first polymeric material is one that (1) is effective to microencapsulate the drug upon completion of the process, (2) is "substantially water-insoluble,” and has appreciable solubility in the selected nonpolar organic solvent i.e.-, the solubility in the selected nonpolar organic solvent is such that the phase separation-coacervation process can be carried out in that solvent, (3) provides for effective taste masking of the drug; and (4) prevents immediate release of the microencapsulated drug in the mouth.
• Ethyl cellulose is particularly preferred as the first polymeric material, although other polymers can be used as well, e.g.
• the most preferred polymers for use as the first polymeric material are the specifically named polymers, in the preceding sentence and combinations of such polymers.
• the preferred polymers are substantially free of readily ionizable substituents such as quaternary ammonium groups and preferably are essentially or entirely free of such substituents.
• substituents such as quaternary ammonium groups
• derivatives of the preferred polymers with substituents such as non-polar substituents can be employed, the most preferred forms of such polymers are essentially free of all substituents.
• references to specific named polymers used as the first polymeric material are intended to refer to the polymers as named, essentially free of substituents.
• Certain preferred polymers have very low solubility for the drug incorporated in the microcapsules, and hence a very low rate of diffusion of the drug through the bulk of the polymer. As further discussed below, it is believed that release of the drug from the microcapsules principally involves pores in the coating rather than diffusion of the drug through the first polymeric material itself.
• the second polymeric material is selected such that it is effective in assisting phase separation of the first polymeric material in the aforementioned process.
• polyethylene is preferred, other polymers may be used as well, e.g.
• the amount of second polymeric material should be selected so as to be at least minimally sufficient to promote phase separation.
• the second polymer may be omitted, so long as alternative means are provided for promoting phase separation of the first polymeric material and formation of microcapsules.
• this process will involve addition of a second solvent effective to assist in and/or induce phase separation of the first polymeric material and microencapsulation of the drug.
• Optional additives which may be incorporated into the microcapsules include deagglomeration agents, i.e., agents effective to reduce microcapsule aggregation (e.g. , colloidal silica such as that available as Syloid®), colorants (e.g., titanium dioxide, dyes suitable for food such as those known as F.D. & C. dyes, etc.), flavoring and/or sweetening agents, and the like.
• deagglomeration agents i.e., agents effective to reduce microcapsule aggregation (e.g. , colloidal silica such as that available as Syloid®), colorants (e.g., titanium dioxide, dyes suitable for food such as those known as F.D. & C. dyes, etc.), flavoring and/or sweetening agents, and the like.
• additives which materially affect the release of the drug preferably are not present in the first polymer layer of the microcapsule. That is, the polymeric portion of the microcapsule desirably consists
• the microcapsules are not coated with any additional layer surrounding the polymeric portion of the capsule. If any such additional layer is employed, it should be formed from a material which is highly water-soluble or should include at least about 10% , and desirably at least about 15 % , of a material which is highly water soluble, so that all or part of the coating will be removed promptly when the microcapsule comes in contact with saliva and/or gastric fluid during use.
• the particle size of the microcapsules will be in the range of a few microns up to about a thousand microns or more, with particle sizes in the approximately 30 ⁇ m to 800 ⁇ m preferred, and particle sizes in the range of approximately 40 ⁇ m to 250 ⁇ m particularly preferred.
• the components of the microcapsules, the relative quantities of drug and polymeric coating material, the size of the microcapsules, and other parameters can easily be varied to provide for different degrees of taste masking and various release profiles.
• the process parameters, microcapsule components, and relative quantities of components described hereinabove will generally provide a "targeted" release profile, i.e., wherein drug release does not generally occur in the mouth, but does occur very shortly thereafter, and is virtually complete within a matter of minutes.
• the targeted- release microcapsules desirably provide dissolution of at least about 75 % of the drug within 45 minutes when tested according to the United States Pharmacopeia, (“USP") dissolution test, using Apparatus 2, commonly referred to in the art as the "paddle method" dissolution test.
• USP United States Pharmacopeia
• the dissolution test referred to herein should be conducted using the dissolution medium, stirring speed and amount of dissolution medium specified in the USP monograph for tablets or capsules of the active ingredient contained in the microcapsules.
• 900 ml of water should be used as the dissolution medium for microcapsules containing less than 5 % of the amount required to form a saturated solution of the active ingredient in 900 ml of water.
• the stirring speed should be 50 rpm, and the temperature should be 37°C. Still higher values of dissolution at 45 minutes, such as at least about 90% dissolution at 45 minutes, are even more desirable. Also, the ability to provide at least about 75 % or even greater dissolution at dissolution times of about 30 minutes, or even more preferably at dissolution times of about 15 minutes, is even more preferred.
• the microcapsules according to preferred embodiments of the present invention desirably provide dissolution of at least that quantity, and preferably Q+5 percent, in the same dissolution test as specified in the monograph.
• the targeted release microcapsules according to the present invention should have a dissolution rate at least as rapid as required to provide the dissolution properties specified in the USP monograph for immediate release tablets or capsules of the active ingredient.
• the targeted release should not be instantaneous in saliva, as instantaneous release of the drug in the patient's mouth would impair taste masking.
• substantial dissolution of the drug during dissolution times of about 1 minute or less is generally not desirable.
• the microcapsules are typically swallowed and pass through the mouth in about 1 minute or less. Lower levels of dissolution during the first minute are associated with more effective taste masking. An ideal taste-masking microcapsule would allow no dissolution of the drug at all in one minute.
• the preferred microcapsules should allow dissolution of considerably less than 75 % of the drug in one minute according to the aforementioned USP test method; lower values of dissolution at one minute such as less than 50% , less than 25% less than 5 % and less than 1 % are still more preferred.
• the present invention is not limited by any theory of operation, it is believed that the polymeric walls of the microcapsules, particularly those formed by coacervation, typically have pores. It is further believed that drug dissolution from the microcapsules occurs through these pores.
• Liquid pharmaceutical compositions containing the present microcapsules will generally be prepared by dispersing or suspending the microcapsules in a non-aqueous carrier which does not cause release of the drug, or else by dispersing the microcapsules in an aqueous carrier immediately prior to administration to the patient.
• the microcapsules may be provided as a free-flowing particulate material, as in a sachet or other suitable package, and such a particulate material may be dispersed in an aqueous carrier.
• These solid or liquid formulations may contain any amount of the microcapsules needed to provide the desired amount of the active ingredient contained in the microcapsules. For example, amounts of microcapsules on the order of 10 wt. % to 95 wt.
• the dosage form should be configured to provide rapid release of the microcapsules when administered to the patient. Stated another way, the elements of the dosage form other than the microcapsules should not greatly impede release of the active ingredient within the microcapsules when the dosage form is administered to a patient.
• the dosage form desirably provides dissolution values such as the preferred dissolution values discussed above with respect to the microcapsules. Actual methods of preparing such dosage forms are known, or will be apparent, to those skilled in this art; for example, see Remington's Pharmaceutical Sciences, 18th Edition (Easton, Pennsylvania: Mack Publishing Company, 1990).
• effervescent formulations incorporate components to promote effervescence, i.e., release of gas upon contact with water; these components include a dry, solid carbonate salt, preferably sodium bicarbonate, and an organic acid such as citric, tartaric, malic, fumaric, adipic and succinic acids. These additives in combination typically represent on the order of 1 wt. % to 90 wt.
• the effervescent formulations may additionally include pharmaceutical grade lubricants such as hydrogenated and partially hydrogenated vegetable oils, animal fats, polyethylene glycol, polyoxyethylene monostearate, talc, light mineral oils, sodium benzoate, sodium lauryl sulfate, magnesium oxide, magnesium stearate, stearic acid, glyceryl behenate, the lubricant sold under the trademark MYVATEX TL by Eastman Chemicals, and the like.
• pharmaceutical grade lubricants such as hydrogenated and partially hydrogenated vegetable oils, animal fats, polyethylene glycol, polyoxyethylene monostearate, talc, light mineral oils, sodium benzoate, sodium lauryl sulfate, magnesium oxide, magnesium stearate, stearic acid, glyceryl behenate, the lubricant sold under the trademark MYVATEX TL by Eastman Chemicals, and the like.
• effervescent tablets suitable for direct oral administration are particularly useful. Such tablets can be arranged to disintegrate rapidly under upon exposure to saliva when placed in the mouth, thereby reducing or eliminating the need for chewing by the patient to cause disintegration. As explained in the '878 patent, this tends to minimize damage to microcapsules incorporated in such an effervescent dosage form.
• Ethyl cellulose 120 g; NF Premium Standard Grade, 100;
• Syloid® Cone 18 5% 5 % 5% 5 % 5 %
• Concentration of ethycellulose is based on 5 % of total cyclohexane weight/volume.
• Concentration of ranitidine HC1 is based on ratio to ethylcellulose in the final microcapsules. 17
• Concentration of polyethylene is based on 0.5 % of total cyclohexane weight.
• Concentration of Syloid® is based on 5 % of total solids (ethylcellulose and ranitidine HC1).
• Example 3 MICROCAPSULE EVALUATION The purpose of this Example 3 was to evaluate the release profile of the microcapsules prepared in Example 2. In Table 2, drug release was evaluated as a function of time for each batch of microcapsules. As may be seen, virtually all of the microcapsules released the majority of encapsulated drug therein within a five minute time period, with over 90% of drug released in 30 to 45 minutes for all microcapsules evaluated.
• Microcapsules containing ranitidine hydrochloride were prepared as described in Example 2.
• Effervescent tablets containing such microcapsules were prepared by weighing the components listed in Table 3 into a poly bag. The admixture thus prepared was passed through a 16US-mesh screen, added to a twin-shell blender and blended for 15 minutes. The lubricant, magnesium stearate, was screened, weighed, and added to the mixture in the twin-shell blender. Blending was continued for an additional 5 minutes. The final blend was discharged and the yield recorded.
• the blend was tableted on a Cad Mach 16 station tablet press equipped with two stations of 0.625", isometric-coated, flat-faced, standard beveled tools positioned opposite each other, and using a gravity feed system.
• Flavor 17.42.7356 5.0 5.0 5.0 5.0 5.0 5.0 5.0
• Thickness 0.126 0.132 0.126 0.126 0.127
• the effervescent tablets prepared in Example 4 were evaluated with respect to drug release over time upon contact with water. Conditions for dissolution testing were as follows.
• Microcapsules containing ranitidine hydrochloride were prepared as described in Example 2.
• Effervescent tablets containing the microcapsules were prepared as described in Example 4.
• microcapsules and effervescent tablets were evaluated for taste-masking by an internal taste panel of eight individuals, each of whom evaluated all of the microcapsules. Four of the five tablet formulations were evaluated by the same eight individuals. Taste evaluation was performed using a standard protocol consisting of: eating a soda cracker; taking a sip of water; and tasting the microcapsule or tablet sample. This sequence was repeated by each subject until all of the samples had been evaluated.
• Microcapsules were evaluated for the following characteristics: flow, color, odor, mouthfeel/ grittiness, taste masking, bitterness, aftertaste, and overall acceptance. The average and median scores for microcapsule taste masking, bitterness, aftertaste, and overall acceptance are shown in FIG. 1A through FIG. ID, and FIG.
• microcapsule composition 2B appears to have the best taste masking score and best overall score.
• Tablet formulations were evaluated for: disintegration time, effervescence level, flavor acceptance, mouthfeel, taste masking, bitterness, aftertaste, and overall acceptance. The average and median scores for microcapsule taste masking, bitterness, aftertaste, and overall acceptance are shown in FIG. 3A through FIG. 3D, and FIG. 4A through FIG. 4D, respectively.
• Tablet formulation 4B, prepared from microcapsule composition 2B appeared to have the best -taste masking score and the best overall score.
• the present invention can be applied in preparation of pharmaceuticals.

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• 1997
  • 1997-10-01 JP JP10516859A patent/JP2000508339A/ja active Pending
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